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Finding the Fourth Proportional to 839.39, 1,159.43 and 645.30

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Solution

The fourth proportional to 839.39, 1,159.43 and 645.30 is: 891.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.39 : 1,159.43 = 645.30 : x
  2. Step 2: Convert to fraction form
    839.39/1,159.43 = 645.30/x
  3. Step 3: Cross multiply
    839.39x = 1,159.43 × 645.30
  4. Step 4: Simplify right side
    839.39x = 748,176.95
  5. Step 5: Solve for x
    x = 748,176.95/839.39
  6. Step 6: Final answer
    x = 891.34

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.